Author: Cale Armstrong Publisher: ISBN: Category : Languages : en Pages :
Book Description
The Kansas Department of Transportation (KDOT) currently practices a six-month procedure for determining freeze-thaw durability of coarse aggregate intended for use in concrete pavement. In addition to the excessive amount of time required to conduct this procedure, the testing conditions fail to replicate the accelerated rate of concrete deterioration commonly caused by deicer salt exposure in freeze-thaw environments. An experimental study was conducted in an attempt to reduce the duration of this aggregate qualification procedure. Limestone course aggregates from different quarries were used to batch concrete specimens. These specimens were subjected to curing regimes of different durations before being exposed to repeated cycles of freezing and thawing. The effects of the curing methods on freeze-thaw durability were then investigated. Another segment of this study entailed the immersion of coarse aggregate in salt brine solution prior to concrete batching. Salt-treated and non-salt-treated specimens were subjected to two different methods of freeze-thaw cycling to determine if the presence of salt could differentiate between aggregates with high and low performance. This study found that shorter curing methods, along with adjusted performance requirements, could be used to develop a shorter aggregate qualification procedure. It also found that shorter periods of time in more severe freeze-thaw conditions produced comparable concrete durability results to those of the current test method. Salt treatment of aggregates could indicate a difference in performance of aggregates when exposed to salts in freeze-thaw conditions. It could also be useful in determining frost resistance of hardened cement paste.
Author: Publisher: ISBN: Category : Pavements, Concrete Languages : en Pages : 69
Book Description
For concrete pavements in Kansas, the most effective method of increasing their sustainability is to increase the service life. One of the principal mechanisms of concrete pavement deterioration in Kansas is freezing and thawing damage. Some Kansas limestone aggregates are known to be very susceptible to D-cracking and have resulted in millions of dollars in maintenance costs. The Kansas Department of Transportation (KDOT) has developed rigorous testing procedures for limestone aggregate use in concrete. In this study, the role of concrete curing, mixture proportioning, and aggregate type on the freeze thaw durability of concrete beams tested using ASTM C 666 method B were investigated. This study found that long periods of soaking in lime water produced more damage during freezing and thawing than standard KDOT curing methods. Curing for shorter period of time in a lime water bath at 100 degrees F, however, gave comparable freeze thaw results to that seen with the longer standard KDOT curing regime. Increasing the concrete's resistance to water penetration can greatly increase the freeze thaw durability of concrete containing D-cracking susceptible aggregates. It was seen that the concrete volume of permeable voids and water absorption rate correlated well with the freeze thaw durability of concrete made with a poor quality aggregates. It is recommended that KDOT continue to enforce concrete permeability and volume of permeable voids specifications to improve the service life of Kansas concrete pavements.
Author: J. Marchand Publisher: CRC Press ISBN: 0203627091 Category : Architecture Languages : en Pages : 323
Book Description
Concrete durability in climates where freezing and thawing occurs is a continuing problem. It is particularly acute for highway and bridge structures, where de-icing salts are used to combat the effects of frost, snow and ice. These salts can cause damage to concrete and accelerate corrosion of reinforcements. This book presents the latest international research on this area, with contributions from North America and Europe which were presented at an international RILEM workshop.
Author: Jonathan Varner Publisher: ISBN: Category : Languages : en Pages :
Book Description
Some limestone coarse aggregate in concrete pavement can break down under repeated freeze-thaw cycles. Application of rock salt may increase the severity of exposure conditions because of trace compounds, such as calcium sulfate, in rock salt. Subsequently, limestone aggregate in concrete was subjected to freeze-thaw cycling in two methods: salt-treating the aggregate before batching concrete, and half-immersing concrete specimens in rock salt solution during freeze-thaw cycling. Concrete and saw-cut limestone specimens were also subjected to wet-dry cycles in varying salt solutions to examine the influence of trace compounds in rock salt. Freeze-thaw test results indicate that the test methods used were not severe enough to determine if a limestone aggregate was durable or not. The wet-dry testing was also not severe enough to determine the effects of trace compounds in salt solution.
Author: Wendell G. Dubberke Publisher: ISBN: Category : Aggregates (Building materials) Languages : en Pages : 32
Book Description
Since 1962, the Iowa DOT has been using the methods of rapid freezing in air and thawing in water to evaluate coarse aggregate durability in concrete. Earlier research had shown that the aggregate pore system was a major factor in susceptibility to D-cracking rapid deterioration. There are cases in which service records indicate that on heavily salted primary roads, concrete containing certain aggregates show rapid deterioration while the same aggregates show relatively good performance on secondary roads with limited use of deicing salt. A fivecycle salt treatment of the coarse aggregate before durability testing has yielded durability factors that correlate with aggregate service records on heavily salted primary pavements. X-ray fluorescence analyses have shown that sulfur contents correlate well with aggregate durabilities with higher sulfur contents that produce poor durability. Trial additives affecting the salt treatment durabilities would indicate that one factor in the rapid deterioration mechanism is an adverse chemical reaction. The objective of the current research is to develop a simple method of determining aggregate susceptibility to salt-related deterioration. This method of evaluation includes analyses of both the pore system and chemical composition.
Author: RH. Vogler Publisher: ISBN: Category : Coarse aggregate Languages : en Pages : 10
Book Description
The procedures used to evaluate the durability of coarse aggregate in concrete by freezing and thawing were determined by a survey. Results indicate that a number of state transportation agencies use freeze-thaw procedures in place of, or in addition to, sulfate soundness and other tests. However, each agency's procedure has unique aspects. ASTM Test Method for Resistance of Concrete to Rapid Freezing and Thawing (C 666) describes the procedures for freeze-thaw cycling and gives partial information on expressing test results, but ASTM has no standard procedure to guide the testing agency in important aspects such as: aggregate grading, aggregate moisture treatment and pretreatment, and concrete mixture proportioning (including cement content, air content of concrete, or curing procedure). The ASTM C 666 method of expressing results for change in length does not permit comparison between different aggregates. The information in this paper is intended to assist ASTM Committee C9 on Concrete and Concrete Aggregates in preparing a practice for evaluation of coarse aggregate in concrete by freezing and thawing.
Author: Publisher: ISBN: Category : Concrete Languages : en Pages : 40
Book Description
SOME OF THE METHODS OF CONCRETE CURING USED IN NEBRASKA WERE EVALUATED. SEVEN CURING METHODS WERE USED, WHICH INCLUDED WATERPROOF PAPER, PLASTIC FILM, WHITE PIGMENTED CURING COMPOUND, WET BURLAP, CLEAR CURING COMPOUND, OR COMBINATIONS OF THESE. THREE 700-FOOT SECTIONS OF CONCRETE PAVEMENT WERE CURED BY EACH METHOD. THE PROJECT WAS CONSTRUCTED DURING COOL, HIGH-HUMIDITY WEATHER - NEAR IDEAL FOR CONCRETE CURING. THE EFFECT OF EACH TYPE OF CURING WAS DETERMINED BY LABORATORY TESTS ON CORES FROM THE PAVEMENT AND BY PAVEMENT CONDITION SURVEYS. THE LABORATORY TESTS ON THE CORES INCLUDED ABRASION TEST, AIR VOID TEST, MIXING WATER TEST, AND STRENGTH TEST. NONE OF THE TESTS SHOWED ANY VARIATION WHICH COULD BE ATTRIBUTED TO CURING METHOD. THE FIELD INSPECTION ALSO SHOWED NO SIGNS OF SURFACE DETERIORATION WHICH COULD BE ATTRIBUTED TO CURING. BECAUSE OF THE COOL, HUMID WEATHER CONDITIONS DURING CONSTRUCTION, LITTLE OR NO DIFFERENCES DUE TO THE CURING MEDIA COULD BE DETECTED.
Author: Craig Walloch Publisher: ISBN: Category : Absorption Languages : en Pages : 28
Book Description
Dry-cast concrete segmental retaining wall (SRW) units and solid interlocking concrete paving units are governed by ASTM C1372 [Standard Specification for Dry-Cast Segmental Retaining Wall Units, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2011] and ASTM C936/C936M [Standard Specification for Solid Concrete Interlocking Paving Units, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2011], respectively. Resistance to freeze-thaw damage is an important performance criterion for these products. These units are produced on machines using vibration-compacted zero-slump concrete. The combination of low water-cement ratio, well-graded aggregates, and intense compaction results in dense, high-strength units without the entrained air necessary in wet-cast concrete to improve freeze-thaw durability. The high-cement content, low-water-cement ratio and short curing time result in a significant percentage of the cement remaining unhydrated. Internal curing (IC) through the use of pre-soaked lightweight aggregates that act as long-term water reservoirs during the cement hydration process is a proven technology that has been optimized in wet-cast concrete to increase the degree of cement hydration and improve durability. For this study, pre-soaked lightweight aggregates were incorporated into SRW units and concrete pavers in an attempt to increase the degree of cement hydration, thereby increasing the quality of the cement paste and improving the freeze-thaw durability of the units. Internally cured SRW units were subjected to ASTM C1262-10 [Standard Test Method for Evaluating the Freeze-Thaw Durability of Dry-Cast Segmental Retaining Wall Units and Related Concrete Units, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2010] freeze-thaw testing. Internally cured concrete pavers were subjected to ASTM C1645-11 [Standard Test Method for Freeze-Thaw and De-Icing Salt Durability of Solid Concrete Interlocking Paving Units, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2011] and CSA A231.2-06 ["Precast Concrete Pavers," Canadian Standards Association, Mississauga, Ontario, Canada, 2006] freeze-thaw testing in 3 % saline solution, as well as ASTM C418 [Standard Test Method for Abrasion Resistance of Concrete by Sandblasting, Annual Book of ASTM Standards, ASTM International, West Conshohocken, PA, 2005] abrasion-resistance testing. The results demonstrate a definite improvement in durability properties of the pavers when internal curing is utilized. In addition, petrographic and scanning electron microscopy studies of the concrete pavers document a significant increase in the degree of cement hydration and quality of the cement paste that is achieved with internal curing. Results of the freeze-thaw tests on SRW units were not conclusive with regard to the effects of internal curing. The petrographic studies of the SRW units showed non-uniform improvement in the degree of cement hydration.
Author: Cale Armstrong
Author: 
Author: J. Marchand
Author: Jonathan Varner
Author: Wendell G. Dubberke
Author: RH. Vogler
Author: William O. Tynes
Author: 
Author: Waterways Experiment Station (U.S.)
Author: Craig Walloch